Liner Glaze

I like TC103 - it's one of Tom Colman's glazes, sold through Aardvark. I tried several liner glaze recipes that I have gotten over the years, and they go matte for me too,but the Coleman's is nice and glossy in a crystal fire.

Marie

Hi Gabriel,

No, I just leave it clear. Since I use a nice white porcelain, it looks white, and creates some lovely effects where I overlap it with my crystalline. If you want an opaque white, you might try TC101. I have used that also, but not in a crystalline fire. It would be cheap to buy a pound and try it out.

Good luck,
Marie

Hi Gabriel,

We also used the TC103 for quite some time and were pretty happy with it. Like Marie says, it is clear, so for it to look white it needs to go on porcelain. We use a small variety of clays and sometimes the non porcelain ones would show speckles in the glaze due to i believe iron particles in the clay.

We switched over to a liner with this recipe...
whiting - 20
custer spar - 40
EPK kaolin - 10
Silica - 30
zircopax - 6-10
water - 100

we have been using this since. I think it was very similar to the coleman clear if the zirco was omitted. It comes out glossy in oxidation and with smaller amounts of zircopax. The more zircopax you use the more satin it gets with 10+ being pretty satin-y. We generally stick to 4-6 zircopax and it is enough to rid any iron speckles and keep it white in the non porcelain bodies but not too much that it still stays glossy. In heavy reduction it can tend to go a bit satin even with the smaller amount of zircopax.

Also with more zircopax (10+) for us it needs to go on much thinner (which if i recall correctly we had trouble with the coleman clear if it went on thin) because it seems the zircopax causes the shrinkage to differ more from the crystal glaze and with crystal on one side and this glaze with 10+ zirco on the other it was cracking our pots.

I would imagine putting zirco in the coleman clear would help whiten but prolly give the same issues we have with the above listed glaze but don't know for sure as we haven't gone that route.

G

I have used colman's TC103 clear for years hat would you recommend I add to it to reduce crazing. I am using it on a porcelain body. When used on a stoneware it does not craze.

Hi Gabriel,

Would it be worth while placing a recipe like Greg's through the Ian Currie Grid test, this will not only yield 35 glazes from one recipe but you should be able to find the sweet spot that works for your porcelain body and 6% zirconium should be fine to give a brilliant or stark white, there is also the way I found my clear and that is by trying 10 bases but this only gave me one workable glaze you may find a different outcome..

Adding more silica should not only fix the crazing issues but also should increase the gloss factor.
Here are the 10 recipes that I tried which can have tin or zircon added to it.

1) Jingdezhen (A)
2) Jingdezhen (B)
3) Dehua (A)
4) Dehua (B)
5) Ding Ware
6) Segar No 4
7) Gong Xian Blue & White
8) Xing Feldspathic
9) Blue Stoneware Base
10) 15th Century Ming /Yongle (Xuande Red)

Hi Gabriel,
I have been using a good liner glaze for some time now in both reduction Cone 10 and crystalline Cone 10

Standard clear Cone 10 (perhaps credited to Tom Coleman)
Custer Feldspar 26.3%
Silica 31.6%
Whiting 21,1%
EPK Kaolin 21%

This glaze is hard, durable, shiny and smooth

Lance

Hi Gabriel,
I had problems with zirconium and prefer the look tin gives. I modified a Stephen Murfitt porcelain glaze to fit my super-smooth white stoneware (available in England) by swapping out half the feldspars for others and increasing silica until the crazing was totally gone. The tin sometimes has a pink tinge when I downfire for large pieces--but I like it. If none of your tests work out, let me know.
-Annie